This invention relates to a cable adjustment mechanism and particularly to one used as a part of a motor vehicle gear selector indicator assembly.
Conventional motor vehicles having automatic transmissions provide a means of visually indicating to the operator the gear shift position. For motor vehicles having conventional column mounted transmission shift levers, the indicator is frequently merely a pointer that moves with a sleeve fitting around the steering column shaft which is rotated by the shift lever. A transparent screen is positioned in front of the pointer with indicia printed on it such that the operator sees the pointer behind one of the indicator marks. In many motor vehicle designs, however, the gear selector indicator cannot be simply mounted to the steering column, due to packaging and styling considerations. It is therefore often necessary to provide a remote control device, typically in the form of a cable, which extends between the gear shift and a transmission selector indicator mounted within the vehicle's instrument panel or console.
Numerous prior art designs for remote control indicator devices of the above type are presently known. In one prior art design exemplified by U.S. Pat. No. 3,695,215, a flexible cable is affixed to the shift lever on the steering column with its opposite end engaging an indicator pointer. Due to manufacturing and assembly tolerance variations in the various components making up the indicator system, some means for properly calibrating the indicated gear position must provided. In the case of the aforementioned U.S. patent, a sliding bracket is employed which enables the position of the cable end with respect to the gear selector to be adjusted. Although this adjustment system operates generally satisfactorily, it requires a degree of operator skill for adjustment and the process is somewhat time consuming. One approach in simplifying the adjustment process is described by U.S. Pat. No. 3,830,192, which discloses an automatic slip clutch arrangement for adjusting the shift position indicator. Such automatic adjustment systems are fairly complex and cannot fully compensate for tolerance variations in all the components influencing the indicated shift position.
The shift selection indicator assemblies in accordance with the present invention improve over prior art devices in that they provide a simplified mechanism which enables accurate and rapid adjustment of the indicated shift position. The present systems include a cable assembly having a cable core which slides through a sheath. The adjustment mechanism has a threaded shaft meshing with a threaded adjustment wheel which changes the effective length of the outer sheath, thus changing the position of the gear selector indicator. A detent is provided so that the adjustment mechanism will remain in a set adjusted condition until an external force is applied to change the adjustment.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings.